Rinse the lentils thoroughly and soak for 30 minutes.
Finely chop the onion, carrot, and celery.
Heat olive oil in a pot and sauté the onion, carrot, and celery.
Add minced garlic for aroma.
Add the soaked lentils, chopped tomatoes, and water or vegetable stock.
Season with salt, pepper, and bay leaves, and bring to a boil.
Simmer over medium-low heat for 25-30 minutes.
Remove the bay leaves and add lemon juice.
Taste and adjust the seasoning, then serve in a bowl.